MreB and MreC represent essential regulators of bacterial cell biology but the mechanism by which they function remains unknown. The identification and characterization of interacting proteins will help elucidate the mechanisms. Since proteins that interact with MreB or MreC are likely to have a similar localization to MreB or MreC, we have conducted a screen for proteins with distinct subcellular localizations in Caulobacter crescentus. This screen will utilize molecular biology, cell growth, and fluorescent microscopy techniques that have been adapted for a high-throughput format. These high-throughput methods will be used to generate a library of spatially and temporally localized proteins in Caulobacter, a prime model system for the study of bacterial cell biology. Once this library of localized proteins is created, I will use this information to study the bacterial proteins MreB and MreC. Specifically, I will identify proteins that localize in a similar pattern as MreB and MreC or proteins whose localization is affected by the loss of functional MreB and MreC, implicating them as potential upstream regulators or downstream effectors. These candidate interacting proteins will then be further characterized to assess their functional relationship with MreB and/or MreC. The research proposed here will provide concrete insights into the functions of these specific proteins, a powerful resource for future Caulobacter functional genomic studies, and a blueprint for other large-scale protein localization studies. The MreB and MreC proteins are essential regulators of bacterial cell processes. Identifying the specific interactions of these proteins will allow a better understanding of the mechanisms they use to function. Once these processes are understood it becomes much easier to create antibiotics that inhibit these essential functions in the bacterial cell. The Gitai laboratory has already proven the validity of this basic science approach by using the increased knowledge of bacterial systems to identify a new antibacterial compound, A22, that specifically targets MreB. This study will provide an increased understanding of MreB and MreC along with a large collection of localized proteins that will be a powerful resource for many projects in the future.